After negotiating the Spire Village, you arrive at the Nali sanctuary of the Sunspire. This towering mountain has been lovingly hollowed out by the Nali to provide a safe haven and sacred place, but now the Skaarj have overrun it and it has become one of the planet's worst nightmares.

You start just beyond the gates on a sloping ledge in a huge mountain valley. In the centre of the valley stands the towering mountain pinnacle of the Sunspire. The following picture was taken looking back from a short way down the ledge.

From your starting point, go left to the edge of the precipice. A long way down in the chasm below is lava. However, you will see a tiny walkway of your ledge going round behind the entrance wall. Follow this walkway to get an ASMD Core. Then, return to the main ledge and enter the gatehouse. A Nali lies slain on the floor, his diary nearby.

"I will not return to the Sunspire today. I was almost slain by the Sky Demon this morning and I fear for our brothers that have not yet escaped. I feel that we will not see them again in this life."

Open the crates in the gatehouse to get a Health Pack. Return to the main ledge and make your way down the slope - lanterns on wooden posts bathe this first stretch in their glow. Soon you will come to a narrow plank bridge over to a freestanding causeway - make your way across.
As you reach the causeway, a SkaarjTrooper with a Dispersion Pistol will see you and come running. Counter-attack with the ASMD primary fire or Eightball Gun locked on - I like to knock the Skaarj off the edge of the causeway so that he falls down towards the lava. When the Skaarj is suitably disposed of, resume your journey along the causeway to the far end; watch out though for the SkaarjInfantry armed with an Eightball Gun at the far end - kill it and grab its Eightball Gun if it doesn't fall off the causeway.
At this end of the causeway, a creaking wooden bridge crosses the lava ravine to the Spire mountain itself. Step on to the bridge - a Nali distress call echoes across the canyon as you do this - and cross to the wooden platform at the mountain entrance. A door lies ahead, with a carving above giving a simple message:

"SunSpire"

Ready your Flak Cannon and go in. Things are about to get nasty.

You will be in the Sunspire's entrance foyer now. There are doorways ahead and to either side, and a stained glass window in the ceiling. Beware as a SkaarjGunner with an Eightball Gun smashes through the ceiling window - kill it quickly before it can harm you.
This entrance room has four pillars. Behind the two nearest to the entrance are two Health Packs. Vases on the inner sides of these two pillars contain two Flares. Next, go behind the pillar that was at the far left as you entered to collect a Razorjack and two boxes of 50 Razor Blades. Then, head to the door opposite the entrance. It has a carved sign over it.

"Primary Ascension"

Enter the room beyond - beware of the Gasbag lurking above the doorway - and look around. The Primary Ascension is a large lift that rises through a large hollow room in the centre of the Spire with several balconies on the way up - but don't use it unless you are taking the shortcut described below. Instead, raid the barrels at the back of the room to get a Stinger and a Health Pack.

Shortcut: You are about to be led on a bounty hunt through all the lower chambers of the Sunspire. If you are just looking for a quick way to get through this first section of the place, then climb on to the lift and ride it to the top of its run. Climb off the lift into the room at the top (go to § ).

Now for the bounty hunt. Return to the main foyer and take the corridor that was to the left as you first entered the Spire. The corridor goes up a slope and into a room with a pillar in the middle, a door on the far side and three small lifts going up and into dark lift shafts. I'll call this the West lift room from now on. I tend to use the Invisibility upon entering this room as there's a SkaarjTrooper with a Dispersion Pistol in the vicinity who runs off to kill the Nali in the next room if you fail to stop him in time.
Go across the room to the door at the far side, which is labelled.

"Chambers of Honour"

A corridor leads you into a room where a Nali prays. The Nali does nothing useful, so open the containers here to grab a Flare and a GES Biorifle. Leave these Chambers of Honour and return to the West lift room.
You are not ready to use any of these lifts yet, so return to the main Spire foyer. Cross the foyer and go through the remaining corridor that you haven't yet explored. It leads to another room similar to the West lift room, but this one is guarded by two Tentacles; this room with three lifts I'll call the East lift room from now on. Kill the Tentacles and open vases for a Flashlight and another Flare. Go through the door at the far end of the room, this one also marked:

"Chambers of Honour"

Climb the ramp and go through the door to the second Chambers of Honour.

This room is similar to the previous Chambers of Honour. A Nali meditates by the lit fire; ignore him and raid the containers. You will find a single Rifle Round (Assault Rifle ammo), an Assault Vest, a Health Pack and a Flare. Collect what you need then return to the East lift room.
Two of the three lifts in the East lift room are labelled.

"Sleeping Chambers"

"Feast Hall"

The third is unlabelled. Take the unlabelled lift to ride to a small corridor, which you should follow round. Entering the next room you will meet a Tentacle and a SkaarjInfantry with a Razorjack whom you should destroy. Raid barrels in this room for a Flashlight, and be sure to collect the Razorjack the Skaarj dropped.
This small room turns into a corridor which descends to the room above the window through which the SkaarjGunner jumped when you first entered the Spire. There is a Gasbag floating here, so kill it. Raid this area for gear; collect two Clips and an Automag lying loose then open containers for a Health Pack and a can of Tarydium Sludge.
There are two exits from this room. One leads up an unlabelled blue corridor guarded by a Tentacle, and the other carries the following label:

"Primary Ascension"

Go through the Primary Ascension door and kill the Gasbag who spots you from inside. As you enter the Primary Ascension area, two Tentacles who attack from either side should also be killed. Open containers from beneath where the Tentacles were for a Flak Shell, a Flare and an ASMD Core.
The room you are currently in turns out to be one of the balconies above the ground floor of the Primary Ascension. Go to the back of the balcony area where there is a lift to the next balcony above, and ride it to the top. The balcony you are then on is patrolled by two SkaarjTroopers with Dispersion Pistols. I remember that on harder skills you will meet SkaarjGunners with Eightball Guns here, so watch out.
This upper balcony has two exits. One leads to a lift upwards - you want the other exit. So, ignore the lift and take the exit on the other side of the balcony through a short corridor into the next room, which is the Feast Hall referred to by the sign in the East lift room.

The Feast Hall has three doors off it. One - the one you just came through - carries a predictable label:

"Primary Ascension"

The second exit anticlockwise is unlabelled. The third however carries a new label:

"Kitchens"

Pause to open a vase in the Feast Hall and retrieve the Flashlight within, then go through the Kitchens door to the dark corridor beyond. Within, with the help of the Flashlight you just collected or a Flare, you will see that the corridor forks. To the right it leads to a lift you don't want to use as part of this route. To the left, it enters the darkened Kitchen area.
The Kitchen is guarded by a Tentacle and Gasbag. Kill them both then retrieve three Flares, a Health Pack and a can of Tarydium Sludge from containers here.
Return to the Feast Hall and take the unlabelled doorway. The corridor beyond shortly ends at a lift shaft; press the button here to call the lift then ride it down. You will find that you emerge from the Feast Hall lift in the East lift room. An extra Gasbag has appeared in the East lift room, so kill it, then take the lift you haven't used yet, the "Sleeping Chambers" lift.
Arriving at the top, you will be in a completely dark corridor. Use a Flare here because as you round the next corner you will be assaulted by a Gasbag and a Tentacle. When the Gasbag and Tentacle are dead, follow the corridor and enter the the first door on the right, which is the first sleeping chamber.

One of the beds has two Flares on top of it. Jump up on to the bed via the skirting board then return to the corridor. Continue along and take the next door on the left; watch out for the Tentacle in this sleeping chamber, then collect the Flare and can of 12 Eightballs available in this room. Cross over the corridor to the adjaicent sleeping chamber, where you can get a fresh Flashlight and another can of 12 Eightballs.
Return to the corridor and visit the final pair of chambers to find a Flare, three Health Packs, a box of 50 Razor Blades, a Clip and another Flashlight. Then, use the corridor and lift to return to the East lift room. You have dealt with this side of the Spire now, so descend the ramp into the main Spire foyer. Cross over and go back up the ramp on the other side, so that you arrive in the West lift room. You only passed briefly through this room before, so take this time to investigate the lifts.
As before, one lift is unlabelled. The others are more informative:

"Bathing Chambers"

"Feast Hall"

The unlabelled lift is no use to you, as it takes you to an area you have visited already. The best area to visit now is the Bathing Chambers area, so ride the Bathing Chambers lift to the top.
The Bathing Chambers corridor is also dark, so toss a Flare. This corridor is different in appearance; it has a polished tiled floor and paler walls. Go along the shiny floor to the first door on the left and enter. A Tentacle here guards a room with a pool of water. Collect two Flares from around the edge of the pool, then open the vases at the back for 40 Tarydium Shards and a box of 8 Rifle Rounds (Assault Rifle ammo). The pool itself contains a Health Pack and a can of 12 Eightballs if you need them.
Return to the Bathing Chambers corridor and go to the far end. From the rooms to either side will attack a Gasbag and a Tentacle, who are best disposed of quickly. When you are done, you can collect the gear on offer; first things first, open the vases in the corridor itself for a Flak Shell and a can of 12 Eightballs.

The door on the left leads to another bathing chamber where a vase contains a Flare, and two Health Packs are available underwater. The other doorway is to a toilet room where vases contain a Flare, three Bandages and a can of Tarydium Sludge. Remember all these Health hot-spots you have uncovered so far, because you may have to come back for them. For now, you have to get moving and really start to progress through the level. So, leave the Bathing Chambers and return to the West lift room.
There's no need to return to the foyer now because all you'll find is an extra Gasbag who has appeared in the corridor. The best way to make progress from here is to take the final lift you haven't used yet - the lift in the West lift room marked "Feast Hall". So, take the Feast Hall lift from the West lift room. Collect the Flare from the corridor at the top, then go round the corner into the hall. Unlike the other Feast Hall, this is dark, lit only by dim Tarydium crystals on the walls.
A SkaarjGunner with a Razorjack will see you as you enter; Flak Bomb it before it can do you any significant damage. Then, go around the room for its rewards; a Flashlight, two Health Packs, an ASMD Core, and the Razorjack the Skaarj dropped. Go and investigate the corridor entrance at the back of the room, which is marked:

"Sleeping Chambers"

The dark corridor beyond is similar to the Sleeping Chambers corridor you visited before. However, this one is not a dead end, continuing after the last Sleeping Chambers at the end. So, kill the Tentacle that attacks you as you enter the corridor, then go to the first pair of sleeping chambers.
The first pair of rooms reveals a can of Tarydium Sludge, two clusters of 40 Tarydium Shards and a Flak Shell, plus containers revealing a Flare and a box of 50 Razor Blades. Continue up the corridor via a Flak Shell on the floor, then explore the other pair of sleeping chambers to get hold of 4 Flak Shells loose plus containers with Tarydium Sludge and a Health Pack.
When you have emptied the rooms, return to the Sleeping Chambers corridor. At this end, the corridor slopes up and round the corner to a lift. Ride the lift and follow the corridor to the top; you will meet a Tentacle in a darkened corridor before coming out in a tall room with a pool at the centre and a tall pillar.
This room is the Spire's water storage tank. Entering, you will be spotted from above by a couple of Gasbags whom you should kill.

A door beyond the pool leads to room at the very top of the Primary Ascension. As you enter this room, the label above the door you just came through will beep on the Universal Translator the name of the room you were just in:

"Cistern"

You've dealt with everything in the lower levels of the Sunspire, so you don't want to go down now. What you can do however is collect thr numerous useful items available in this area.§ In this room at the top of the Primary Ascension two Health Packs are available. If you open the containers, you can also grab a Flare, Bandages and an extremely useful box of 10 Flak Shells. A corridor off to one side leads only to a lift back down into the lower levels of the Spire, so go back through the doors labelled "Cistern" to the Spire's water storage area.
You may think if you have been following the bounty hunt route that you have run out of places to go, but you're not. Take a dive into the Cistern's water pool itself (via the Health Pack at the bottom if necessary) and you will see an underwater pipe leading off to the side.
Follow the water-filled pipe and you will reach an underwater sump tank where you can get an ASMD and ASMD Core if required. Then, swim up and surface for air at the top of the sump. A tunnel leads off to the side here, so follow it along to the end, where a wall opens. Beyond is another dark-ish room; a small tank conceals within and below three nast Skaarj Pupae - use your ASMD or Automag to kill these fast scuttling biting creatures. When you're done killing the Pupae, open containers in this small room for a Flare, a Health Pack and a Rifle Round.
Looking around, you will see that a dark corridor leaves this room. Follow it with the help of a portable light source, and you will see that once again it forks. To the right it leads to a lift downwards that you don't want to take as it would be backtracking. To the left, the corridor leads to a storage chamber. Containers in the storage chamber reveal useful goodies in the form of a Flare, a box of 50 Razor Blades and a Rifle Round, but will also reveal two Pupae. Keep your guard up.
From the storage room, the corridor doubles back on itself and goes round a corner. Continue to follow it and you will be at a darkened T-junction, where there is a sign:

"Great Hall."

Shoot open a vase at the T-junction for a Flashlight (you probably need a new one by now), then take the left turn. You will be led up a ramp and then arrive on a balcony above the Great Hall, where a Pupae drops down from the ceiling. You can collect 5 Flares from the balcony and a can of Tarydium Sludge from a nearby door frame.

Go down to the ground floor of the hall, either by the corridor or by dropping off the balcony. Collect the 3 Flares from under the balcony, then use one of them to illuminate the shadows there; you will see a lever on the wall which you can press. When you press the lever, the alter at the head of the Great Hall rises. Go round behind it and you can collect a Minigun from a revealed compartment in the altar itself.
There are two doors from the ground floor of the Great Hall. One is the way down from the junction by which you entered, and the other is seemingly a dead end. However, once you have the Minigun, a lift descends a shaft into the dead end and you can use it to ride to the next floor up.
At the top of the lift shaft, you at last return to the mainstream lit part of the Spire. You will be in a small antechamber with a lift ahead, and a corridor to the right. Beware the Pupae who comes out of the lift shaft as you approach. This room also contains 2 Flak Shells, plus a Health Pack in a vase. The way onwards is up the lift, but first take a moment to follow the corridor to the right. You will come out on a balcony some considerable height above the Cistern, where you will meet a SkaarjInfantry with a Stinger and two Pupae, plus any Gasbags who didn't see you whilst you were down below. You do get the bonus though of the Stinger the Skaarj dropped plus containers with a Health Pack, 50 Razor Blades and a very useful box of 10 Flak Shells.
If you look down towards the Cistern you will see a cross-beam with a Health Pack and a can of 12 Eightballs. I have never tried to get them because of the falling hazard but you can have a go if you want! If you try, beware extra Pupae who will have appeared in various places around the lower levels of the Spire.
When you're done, return to the antechamber at the bottom of the lift you haven't yet used. Ride the lift and you will follow a short corridor into another antechamber. Be sure to open the vase here for a Flare, then ignore the two lift shafts on the right and go straight on.
Another short corridor later, you'll be in yet another antechamber. Kill the two Tentacles in this room and collect of the two Health Packs. Open containers for a Flare, two more Health Packs, a box of 10 Flak Shells and an Invisibility inventory item. Follow the corridor on round from here and you will be in a room where a SkaarjTrooper with a Dispersion Pistol crouches by some human bodies. Kill the Skaarj then collect the Automag and Nali Fruit Seed here, and open barrels for two Bandages. Investigate the corpses - two carry log entries:

"Log: Petty Officer N. Onalopov: We split up so we would have a better chance of finding Kira. Those bastards are going to pay for taking her. I love you Kira, I swear I'll find you."

"Log: Security Officer A. Connectof: We are running out of ammo fast. There's only one weapon left. We have to reach the top where we can activate the SkyElevator, according to the Nali at the gates."

The room will lead you through a door and out onto a windy ledge outside the Spire - it's a long way down. To the right, a barrel contains Razor Blades. To the left, the ledge winds up the side of the mountain. Climb the ledge. On the way up you will encounter a SkaarjGunner with an Eightball Gun; kill it and collect his weapon. Beware if you go back down for anything, because another SkaarjGunner with an Eightball Gun has appeared.

Near the top, the ledge flattens out. Beware the Pupae lurking behind a lantern post at this point. At the end, the ledge ends, but a doorway goes back inside the mountain. Enter again, killing the Tentacle within. Inside after a short stretch, the corridor turns right at a small room (where barrels contain a Clip). Kill the Tentacle and Gasbag who attack from the right, then dispose of the Gasbag who appears behind you in the corridor by which you entered. When you're done, follow the corridor as it winds round until you reach an antechamber guarded by a Tentacle and a SkaarjInfantry with a Razorjack. Kill the creatures then take the Razorjack the Skaarj was wielding. Open barrels for two Health Packs.
There are four lift shafts in this antechamber. Two go down, two go up. Ignore the ones going down; the ones going up go to the same place as each other, so get on either (one is already at this level, the other you will have to call first), and after a very long ride up a red-lit lift shaft you will be in a high-altitude antechamber where you can hear the wind rumbling away. Kill the two Tentacles here - be very careful not to accidentally back down one of the lift shafts as you will fall to your death! When they are dead, open the barrels here to get two Health Packs and a can of Tarydium Sludge.
Almost there now! Take the corridor out of this room; it forks into a corridor on the left and a labelled door ahead.

"Chamber of Crystals"

If you approach the door it will open and you will meet a SkaarjInfantry with a Razorjack. Kill it but don't go inside (except for the Razorjack it drops), because you are not ready to operate the crystal yet. Return to the corridor and follow it round; beware in the next stretch leading up to a door another SkaarjInfantry with a Razorjack; kill it and collect its weapon.
Open the door at the end of the corridor and go through into a grass-floored room beyond. Kill the Tentacle and two Pupae who attack within, then look around. To the right are two Health Packs and to the left a Barrel with an ASMD Core. Ahead is a staircase you can ignore for now. Go instead to the left of the staircase and open barrels beneath the staircase for a Health Pack, Clip and box of 50 Bullets. A doorway in this corner of the grass-floored room leads outside on to the top of the Spire. Be careful not to fall off throughout the next section, it's a long way to fall!
Go out through the door and on to the plateau. Outside, you will have an altercation with two or three Gasbags. Kill them, then open barrels out here for two packs of Razor Blades and a Health Pack. Follow the plateau round the central building - beware the Pupae that attacks from behind a pillar on the left - on to another part of the plateau where another SkaarjInfantry with a Razorjack has a go. Kill it too and take its gun.

In this area, an alcove under a balcony above contains a very useful Super Health Pack. Collect it then return to the plateau. If you look at the end of the stone wall here, you will see a narrow strip of plateau extending round the end. Follow it round then go round into a hidden area behind the wall where a Pupae guards four Flak Shells, two ASMD Cores and two Health Packs. Collect.
At last it is time to leave this blighted Nali sanctuary. Go back inside the building and return via the corridor to the Chamber of Crystals. Collect if necessary a Health Pack from the shadows at the back of the room, then press the lever by the structure in the centre of the room. Before your eyes, a Tarydium Crystal will rise out of the floor and send lightning beams up to the ceiling.
Return to the grassy room insode on the plateau, and climb the steps you ignored before. You will arrive on a balcony above the plateau, passing a sign that reads:

"Prepare to Embark"

As you wait, you will see an ornate cabin descend slowly out of the sky and a door slowly open. When it halts at balcony level, step inside. Shortly, the door will close as you rise gently from the roof and exit the level.